Robust 5 kV RMS Isolated RS-485/RS-422 Transceiver with Level 4 EMC and Full 42 V Protection ADM2795E Data Sheet FEATURES APPLICATIONS 5 kV rms isolated RS-485/RS-422 transceiver 42 V ac/dc peak fault protection on RS-485 bus pins Certified Level 4 EMC protection on RS-485 A, B bus pins IEC 61000-4-5 surge protection (4 kV) IEC 61000-4-4 electrical fast transient (EFT) protection (2 kV) IEC 61000-4-2 electrostatic discharge (ESD) protection 8 kV contact discharge 15 kV air discharge IEC 61000-4-6 conducted radio frequency (RF) immunity (10 V/m rms) Certified IEC 61000-4-x immunity across isolation barrier IEC 61000-4-2 ESD, IEC 61000-4-4 EFT, IEC 61000-4-5 surge, IEC 61000-4-6 conducted RF immunity, IEC 61000-4-3 radiated immunity, IEC 61000-4-8 magnetic immunity RS-485 A, B pins human body model (HBM) ESD protection: >30 kV Safety and regulatory approvals (pending) CSA Component Acceptance Notice 5A, DIN V VDE V 0884-10, UL 1577, CQC11-471543-2012 TIA/EIA RS-485/RS-422 compliant over full supply range 3 V to 5.5 V operating voltage range on VDD2 1.7 V to 5.5 V operating voltage range on VDD1 logic supply Common-mode input range of -25 V to +25 V High common-mode transient immunity: >75 kV/s Robust noise immunity (tested to the IEC 62132-4 standard) Passes EN55022 Class B radiated emissions by 6 dBV/m margin Receiver short-circuit, open-circuit, and floating input fail-safe Supports 256 bus nodes (96 k receiver input impedance) -40C to +125C temperature option Glitch free power-up/power-down (hot swap) Heating, ventilation, and air conditioning (HVAC) networks Industrial field buses Building automation Utility networks GENERAL DESCRIPTION The ADM2795E is a 5 kV rms signal isolated RS-485 transceiver that features up to 42 V of ac/dc peak bus overvoltage fault protection on the RS-485 bus pins. The device integrates Analog Devices, Inc., iCoupler(R) technology to combine a 3-channel isolator, RS-485 transceiver, and IEC electromagnetic compatibility (EMC) transient protection in a single package. The ADM2795E is a RS-485/RS-422 transceiver that integrates IEC 61000-4-5 Level 4 surge protection, allowing up to 4 kV protection on the RS-485 bus pins (A and B). The device has IEC 61000-4-4 Level 4 EFT protection up to 2 kV and IEC 61000-4-2 Level 4 ESD protection on the bus pins, allowing this device to withstand up to 15 kV on the transceiver interface pins without latching up. This device has an extended common-mode input range of 25 V to improve data communication reliability in noisy environments. The ADM2795E is capable of operating over wide power supply ranges, with a 1.7 V to 5.5 V VDD1 power supply range, allowing interfacing to low voltage logic supplies. The ADM2795E is also fully TIA/EIA RS-485/RS-422 compliant when operated over a 3 V to 5.5 V VDD2 power supply. The device is fully characterized over an extended operating temperature range of -40C to +125C, and is available in a 16-lead, wide-body SOIC package. FUNCTIONAL BLOCK DIAGRAM VDD1 VDD2 DIGITAL ISOLATOR RS-485 TRANSCEIVER ADM2795E RxD RE EMC TRANSIENT PROTECTION CIRCUIT DE A B GND1 GND2 ISOLATION BARRIER 14129-001 TxD Figure 1. Rev. B Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 (c)2016-2020 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com ADM2795E Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Overvoltage Fault Protection .................................................... 16 Applications ....................................................................................... 1 42 V Miswire Protection ......................................................... 16 General Description ......................................................................... 1 RS-485 Network Biasing and Termination ............................. 16 Functional Block Diagram .............................................................. 1 IEC ESD, EFT, and Surge Protection ....................................... 17 Revision History ............................................................................... 2 IEC Conducted, Radiated, and Magnetic Immunity............. 21 Specifications..................................................................................... 3 Applications Information .............................................................. 23 Timing Specifications .................................................................. 4 Radiated Emissions and PCB Layout ...................................... 23 Insulation and Safety-Related Specifications ............................ 5 Noise Immunity .......................................................................... 23 Package Characteristics ............................................................... 5 Fully RS-485 Compliant over an Extended 25 V CommonMode Voltage Range .................................................................. 23 Regulatory Information ............................................................... 5 DIN V VDE V 0884-10 (VDE V 0884-10) Insulation Characteristics .............................................................................. 6 1.7 V to 5.5 V VDD1 Logic Supply.............................................. 23 Truth Tables................................................................................. 24 Absolute Maximum Ratings............................................................ 7 Receiver Fail-Safe ....................................................................... 24 Thermal Resistance ...................................................................... 7 RS-485 Data Rate and Bus Capacitance .................................. 24 ESD Caution .................................................................................. 7 Insulation Wear Out .................................................................. 24 Pin Configuration and Function Descriptions ............................. 8 Hot Swap Capability................................................................... 25 Typical Performance Characteristics ............................................. 9 Robust Half-Duplex RS-485 Network ..................................... 25 Test Circuits ..................................................................................... 13 Switching Characteristics .......................................................... 14 EMC Compliant and Fault Protected Signal and Power Isolated RS-485 Node ................................................................ 27 Theory of Operation ...................................................................... 15 Outline Dimensions ....................................................................... 28 RS-485 with Robustness ............................................................ 15 Ordering Guide .......................................................................... 28 Integrated and Certified IEC EMC Solution .......................... 15 REVISION HISTORY 1/2020--Rev. A to Rev. B Added EMC Compliant and Fault Protected Signal and Power Isolated RS485 Node Section, Table 2; Renumbered Sequentially, and Figure 53; Renumbered Sequentially ............ 27 3/2017--Rev. 0 to Rev. A Changes to Table 5 ............................................................................ 5 Changes to DIN V VDE V 0884-10 (VDE V 0884-10) Insulation Characteristics Section .................................................. 6 10/2016--Revision 0: Initial Version Rev. B | Page 2 of 28 Data Sheet ADM2795E SPECIFICATIONS 1.7 V VDD1 5.5 V, 3 V VDD2 5.5 V, TA = -40C to +125C. All minimum/maximum specifications apply over the entire recommended operation range, unless otherwise noted. All typical specifications at TA = 25C, VDD1 = VDD2 = 5.0 V, unless otherwise noted. Table 1. Parameter SUPPLY CURRENT Power Supply Current Logic Side TxD/RxD Data Rate = 2.5 Mbps Bus Side TxD/RxD Data Rate = 2.5 Mbps Supply Current in Shutdown Mode DRIVER Differential Outputs Differential Output Voltage Symbol Input Capacitance (A, B) Line Input Resistance Typ IDD1 IDD2 Max Unit Test Conditions/Comments 10 10 12 90 130 mA mA mA mA mA Unloaded output, DE = VDD1, RE = 0 V Unloaded output, DE = VDD1, RE = 0 V Unloaded output, DE = VDD1, RE = 0 V Unloaded output, DE = VDD1, RE = 0 V DE = VDD1, RE = 0 V, VDD2 = 5.5 V, R = 27 , see Figure 27 DE = VDD1, RE = 0 V, VDD2 = 5.5 V, R = 27 , see Figure 27 DE = VDD1, RE = 0 V, VDD2 = 3.0 V, R = 27 , see Figure 27 DE = 0 V, RE = VDD1 94 mA 46 mA ISHDN 10 mA 1.5 5.0 V 2.1 5.0 V 1.5 5.0 V 2.1 5.0 V |VOD| 0.2 V VDD2 3.0 V, R = 27 or 50 , see Figure 27 VDD2 4.5 V, R = 27 or 50 , see Figure 27 VDD2 3.0 V, VCM = -25 V to +25 V, see Figure 28 VDD2 4.5 V, VCM = -25 V to +25 V, see Figure 28 R = 27 or 50 , see Figure 27 VOC |VOC| 3.0 0.2 V V R = 27 or 50 , see Figure 27 R = 27 or 50 , see Figure 27 +250 +250 mA mA -42 V VSC +42 V 1 -42 V VSC +42 V1 0.33 x VDD1 V V A 1.7 V VDD1 5.5 V 1.7 V VDD1 5.5 V 0 V VIN VDD1 mV mV mA mA pF k -25 V VCM +25 V -25 V VCM +25 V DE = 0 V, VDD2 = 0 V/5 V, VIN = 25 V DE = 0 V, VDD2 = 0 V/5 V, VIN = 42 V TA = 25C, see Figure 17 -25 V VCM +25 V, up to 256 nodes supported |VOD| |VOD3| Change in Differential Output Voltage for Complementary Output States Common-Mode Output Voltage Change in Common-Mode Output Voltage for Complementary Output States Short-Circuit Output Current VOUT = Low VOUT = High Logic Inputs (DE, RE, TxD) Input Threshold Low Input Threshold High Input Current RECEIVER Differential Inputs Differential Input Threshold Voltage Input Voltage Hysteresis Input Current (A, B) Min IOSL IOSH -250 -250 VIL VIH ITxD 0.7 VDD1 VTH VHYS II CAB RIN +1 -200 -125 30 -1.0 -1.0 -30 +1.0 +1.0 150 96 Rev. B | Page 3 of 28 ADM2795E Data Sheet Parameter Logic Outputs Output Voltage Low Output Voltage High Short-Circuit Current Three-State Output Leakage Current Symbol Min VOLRxD VOHRxD VDD1 - 0.2 2 Max Unit Test Conditions/Comments 0.2 V V mA A IORxD = 3.0 mA, VA - VB = -0.2 V IORxD = -3.0 mA, VA - VB = 0.2 V VOUT = GND or VDD1, RE = 0 V RE = VDD1, RxD = 0 V or VDD1 kV/s VCM 1 kV, transient magnitude 800 V 100 2 IOZR COMMON-MODE TRANSIENT IMMUNITY 2 1 Typ 75 125 VSC is the short-circuit voltage at the RS-485 A or B bus pin. Common-mode transient immunity is the maximum common-mode voltage slew rate that can be sustained while maintaining specification-compliant operation. VCM is the common-mode potential difference between the logic and bus sides. The transient magnitude is the range over which the common mode is slewed. The common-mode voltage slew rates apply to both rising and falling common-mode voltage edges. TIMING SPECIFICATIONS VDD1 = 1.7 V to 5.5 V, VDD2 = 3.0 V to 5.5 V, TA = TMIN to TMAX (-40C to +125C), unless otherwise noted. Table 2. Parameter DRIVER 1 Maximum Data Rate Propagation Delay, tDPLH, tDPHL Differential Skew, tSKEW Rise/Fall Times, tR, tF Enable Time, tZH, tZL Disable Time, tHZ, tLZ RECEIVER 2 Propagation Delay, tPLH, tPHL Skew, tSKEW Enable Time Disable Time RxD Pulse Width Distortion 1 2 Min Typ Max Unit Test Conditions/Comments 30 10 40 500 500 500 50 130 2500 2500 Mbps ns ns ns ns ns RLDIFF = 54 , CL1 = CL2 = 100 pF, see Figure 29 and Figure 33 RLDIFF = 54 , CL1 = CL2 = 100 pF, see Figure 29 and Figure 33 RLDIFF = 54 , CL1 = CL2 = 100 pF, see Figure 29 and Figure 33 RL = 110 , CL = 50 pF, see Figure 30 and Figure 35 RL = 110 , CL = 50 pF, see Figure 30 and Figure 35 120 140 4 10 10 200 220 40 50 50 40 ns ns ns ns ns ns CL = 15 pF, see Figure 31 and Figure 34, 10, VID 1.5 V CL = 15 pF, see Figure 31 and Figure 34, VID 600 mV CL = 15 pF, see Figure 31 and Figure 34, VID 1.5 V RL = 1 k, CL = 15 pF, see Figure 32 and Figure 36 RL = 1 k, CL = 15 pF, see Figure 32 and Figure 36 CL = 15 pF, see Figure 31 and Figure 34, VID 1.5 V 2.5 See Figure 29 for the definition of RLDIFF. Receiver propagation delay, skew, and pulse width distortion specifications are tested with a receiver differential input voltage (VID) of 600 mV or 1.5 V, as noted. Rev. B | Page 4 of 28 Data Sheet ADM2795E INSULATION AND SAFETY-RELATED SPECIFICATIONS For additional information, see www.analog.com/icouplersafety. Table 3. Parameter Rated Dielectric Insulation Voltage Minimum External Air Gap (Clearance) Symbol L(I01) Value 5000 7.8 Unit V rms mm min Minimum External Tracking (Creepage) L(I02) 7.8 mm min Minimum Clearance in the Plane of the Printed Circuit Board (PCB Clearance) L(PCB) 8.3 mm min CTI 25.5 >400 II m min V Minimum Internal Gap (Internal Clearance) Tracking Resistance (Comparative Tracking Index) Material Group Conditions 1 minute duration Measured from input terminals to output terminals, shortest distance through air Measured from input terminals to output terminals, shortest distance along body Measured from input terminals to output terminals, shortest distance through air, line of sight, in the PCB mounting plane Minimum distance through insulation DIN IEC 112/VDE 0303 Part 1 Material Group (DIN VDE 0110, 1/89) PACKAGE CHARACTERISTICS Table 4. Parameter Resistance (Input to Output) 1 Capacitance (Input to Output)1 Input Capacitance 2 Input Capacitance, A and B Pins IC Junction to Ambient Thermal Resistance 1 2 Symbol RI-O CI-O CI CAB JA Min Typ 1013 2.2 4.0 150 59.7 Max Unit pF pF pF C/W Test Conditions/Comments f = 1 MHz TA = 25C, see Figure 17 Thermocouple located at center of package underside The device is considered a 2-terminal device: Pin 1 through Pin 8 are shorted together, and Pin 9 through Pin 16 are shorted together. Input capacitance is from any digital input pin to ground. REGULATORY INFORMATION See Table 8 and the Insulation Wear Out section for details regarding recommended maximum working voltages for specific cross isolation waveforms and insulation levels. The ADM2795E is approved or pending approval by the organizations listed in Table 5. Table 5. ADM2795E Approvals UL Recognized Under UL 1577 Component Recognition Program 1 Single Protection, 5000 V rms Isolation Voltage File E214100 1 2 CSA Approved under CSA Component Acceptance Notice 5A VDE Certified according to DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 2 CSA 60950-1-07+A1+A2 and IEC 60950-1 second edition +A1+A2: Basic insulation at 780 V rms (1103 V peak) Reinforced insulation at 390 V rms (552 V peak) IEC 60601-1 Edition 3.1: 1 means of patient protection (MOPP), 400 V rms (566 V peak) 2 MOPP, 237 V rms (335 V peak) CSA 61010-1-12+A1 and IEC 61010-1 third edition: Basic insulation at 600 V rms mains (Overvoltage Category III), 780 V secondary (1103 V peak) File 205078 Reinforced insulation, VIORM = 849 V peak, VIOSM = 8000 V peak File 2471900-4880-0001/231230 In accordance with UL 1577, each ADM2795E is proof tested by applying an insulation test voltage 6000 V rms for 1 sec. In accordance with DIN V VDE V 0884-10, each ADM2795E is proof tested by applying an insulation test voltage 1592 V peak for 1 sec. Rev. B | Page 5 of 28 CQC (Pending) Certified by CQC11-471543-2012, GB4943.1-2011 Basic insulation at 780 V rms (1103 V peak) Reinforced insulation at 389 V rms (552 V peak) File (pending) ADM2795E Data Sheet DIN V VDE V 0884-10 (VDE V 0884-10) INSULATION CHARACTERISTICS This isolator is suitable for reinforced electrical isolation only within the safety limit data. Maintenance of the safety data must be ensured by means of protective circuits. An asterisk (*) on a package denotes VDE 0884 approval for an 849 V peak working voltage. Table 6. Description Installation Classification per DIN VDE 0110 for Rated Mains Voltage 150 V rms 300 V rms 400 V rms Climatic Classification Pollution Degree (DIN VDE 0110, see Table 3) Maximum Working Insulation Voltage Input to Output Test Voltage, Method b1 Input to Output Test Voltage, Method a After Environmental Tests, Subgroup 1 After Input and/or Safety Test, Subgroup 2/Subgroup 3 Highest Allowable Overvoltage Reinforced Surge Isolation Voltage Safety Limiting Values Total Power Dissipation at TA = 25C Insulation Resistance at TS Test Conditions/Comments VIORM x 1.875 = VPR, 100% production tested, tm = 1 sec, partial discharge < 5 pC Transient overvoltage, tTR = 10 sec VPEAK = 12.8 kV, 1.2 s rise time, 50 s, 50% fall time Maximum value allowed in the event of a failure, see Figure 2 VIO = 500 V SAFE LIMITING POWER (W) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 50 100 150 14129-002 0.2 AMBIENT TEMPERATURE (C) Unit VIORM VPR I to IV I to IV I to III 40/125/21 2 849 1592 V peak V peak 1274 1019 V peak V peak VIOTM VIOSM TS 7000 8000 150 V peak V peak C PS RS 1.80 >109 W VPR 1.8 0 Characteristic VIORM x 1.5 = VPR, tm = 60 sec, partial discharge < 5 pC VIORM x 1.2 = VPR, tm = 60 sec, partial discharge < 5 pC 2.0 0 Symbol Figure 2. Thermal Derating Curve for RW-16 Wide Body [SOIC_W] Package, Dependence of Safety Limiting Values with Ambient Temperature per DIN V VDE V 0884-10 Rev. B | Page 6 of 28 Data Sheet ADM2795E ABSOLUTE MAXIMUM RATINGS TA = 25C, unless otherwise noted. Table 8. Maximum Continuous Working Voltage1 Table 7. Parameter AC Voltage Bipolar Waveform Basic Insulation Parameter VDD1 VDD2 Digital Input/Output Voltage (DE, RE, TxD, RxD) Driver Output/Receiver Input Voltage Operating Temperature Range Storage Temperature Range Maximum Junction Temperature Continuous Total Power Dissipation Lead Temperature Soldering (10 sec) Vapor Phase (60 sec) Infrared (15 sec) ESD (A, B Pins Tested to GND2) IEC 61000-4-2 Contact Discharge IEC 62000-4-2 Air Discharge EFT (A, B Pins Tested to GND2) IEC 61000-4-4 Level 4 EFT Protection Surge (A, B Pins Tested to GND2) IEC 61000-4-5 Level 4 Surge Protection EMC Performance from A, B Bus Pins Across the Isolation Barrier to GND1 ESD IEC 61000-4-2 Contact Discharge IEC 61000-4-2 Air Discharge EFT IEC 61000-4-4 Surge IEC 61000-4-5 HBM ESD Protection (A, B Pins Tested to GND2) HBM ESD Protection (All Pins) Field Induced Charged Device Model ESD (FICDM) Rating -0.5 V to +7 V -0.5 V to +7 V -0.3 V to VDD1 + 0.3 V Reinforced Insulation 48 V -40C to +125C -65C to +150C 150C 405 mW Unipolar Waveform Basic Insulation Reinforced Insulation 300C 215C 220C 8 kV 15 kV DC Voltage Basic Insulation Max Unit Reference Standard2 849 V peak 768 V peak 50-year minimum insulation lifetime Lifetime limited by package creepage maximum approved working voltage per IEC 60950-1 1698 V peak 885 V peak 1092 V peak 543 V peak 2 kV 4 kV Reinforced Insulation 9 kV 8 kV 50-year minimum insulation lifetime Lifetime limited by package creepage maximum approved working voltage per IEC 60950-1 Lifetime limited by package creepage maximum approved working voltage per IEC 60950-1 Lifetime limited by package creepage maximum approved working voltage per IEC 60950-1 The maximum continuous working voltage refers to the continuous voltage magnitude imposed across the isolation barrier. See the Insulation Wear Out section for more details. 2 Insulation lifetime for the specified test condition is greater than 50 years. 1 2 kV THERMAL RESISTANCE 4 kV >30 kV Thermal performance is directly linked to PCB design and operating environment. Careful attention to PCB thermal design is required. 6 kV 1.25 kV Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability. JA is the natural convection junction to ambient thermal resistance measured in a one cubic foot sealed enclosure. JC is the junction to case thermal resistance. Table 9. Thermal Resistance Package Type RW-16 1 JA1 59.7 JC1 28.3 Unit C/W Thermal impedance simulated values are based on a JEDEC 2S2P thermal test board with no vias. See JEDEC JESD51. ESD CAUTION Rev. B | Page 7 of 28 ADM2795E Data Sheet PIN CONFIGURATION AND FUNCTION DESCRIPTIONS VDD1 1 16 VDD2 15 GND2 2 TxD 3 DE 4 RE 5 RxD 6 NIC 7 GND1 8 ADM2795E 14 B 13 VDD2 TOP VIEW (Not to Scale) 12 GND2 11 A 10 GND2 9 GND2 NOTES 1. NIC = NOT INTERNALLY CONNECTED. 14129-003 GND1 Figure 3. Pin Configuration Table 10. Pin Function Descriptions Pin No. 1 2 3 4 Mnemonic VDD1 GND1 TxD DE 5 RE 6 7 8 9 10 11 RxD NIC GND1 GND2 GND2 A 12 13 14 GND2 VDD2 B 15 16 GND2 VDD2 Description 1.7 V to 5.5 V Flexible Logic Interface Supply. Ground 1, Logic Side. Transmit Data Input. Data to be transmitted by the driver is applied to this input. Driver Output Enable. A high level on this pin enables the driver differential outputs, A and B. A low level places them into a high impedance state. Receiver Enable Input. This pin is an active low input. Driving this input low enables the receiver, and driving it high disables the receiver. Receiver Output Data. This output is high when (A - B) > -30 mV and low when (A - B) < -200 mV. Not Internally Connected. This pin is not internally connected. Ground 1, Logic Side. Isolated Ground 2, Bus Side. Isolated Ground 2, Bus Side. Noninverting Driver Output/Receiver Input. When the driver is disabled, or when VDD1 or VDD2 is powered down, Pin A is put into a high impedance state to avoid overloading the bus. Isolated Ground 2, Bus Side. 3 V to 5.5 V Power Supply. Pin 13 must be connected externally to Pin 16. Inverting Driver Output/Receiver Input. When the driver is disabled, or when VDD1 or VDD2 is powered down, Pin B is put into a high impedance state to avoid overloading the bus. Isolated Ground 2, Bus Side. 3 V to 5.5 V Power Supply. Pin 16 must be connected externally to Pin 13. Rev. B | Page 8 of 28 Data Sheet ADM2795E TYPICAL PERFORMANCE CHARACTERISTICS 4.5 90 SUPPLY CURRENT (mA) 80 70 60 IDD2, 120 LOAD 50 40 30 IDD2, NO LOAD 20 IDD1 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 -40 14129-004 10 VDD1 = VDD2 = 5.5V 4.0 -20 0 20 40 60 80 100 14129-007 VDD1 = VDD2 = 5.5 V IDD2, 54 LOAD DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V) 100 120 TEMPERATURE (C) Figure 4. Supply Current (ICC) vs. Temperature at RL = 54 , 120 , and No Load; Data Rate = 2.5 Mbps, VDD1 = 5.5 V, VDD2 = 5.5 V Figure 7. Driver Differential Output Voltage vs. Temperature 60 0 VDD1 = 1.7V, VDD2 = 3.0V -0.02 50 DRIVER OUTPUT CURRENT (A) 40 IDD2, 120 LOAD 30 20 IDD2, NO LOAD IDD1 -20 -0.08 -0.10 -0.12 -0.14 0 20 40 60 80 100 120 TEMPERATURE (C) -0.16 DRIVER OUTPUT HIGH VOLTAGE (V) Figure 8. Driver Output Current vs. Driver Output High Voltage Figure 5. Supply Current (ICC) vs. Temperature at RL = 54 , 120 , and No Load; Data Rate = 2.5 Mbps, VDD1 = 1.7 V, VDD2 = 3.0 V 0.14 0.01 VDD1 = 1.7V, VDD2 = 3.0V 0.12 DRIVER OUTPUT CURRENT (A) -0.04 -0.09 -0.14 VDD1 = 4.5V, VDD2 = 4.5V -0.19 VDD1 = 5.5V, VDD2 = 5.5V -0.24 -0.29 0.10 VDD1 = 1.7V, VDD2 = 3.0V PIN A VDD1 = 1.7V, VDD2 = 3.0V PIN B VDD1 = 5.5V, VDD2 = 5.5V PIN A VDD1 = 5.5V, VDD2 = 5.5V PIN B 0.08 0.06 0.04 -0.39 0 1 2 3 4 5 DIFFERENTIAL OUTPUT VOLTAGE (V) 6 0 0 5 10 15 20 25 DRIVER OUTPUT LOW VOLTAGE (V) Figure 9. Driver Output Current vs. Driver Output Low Voltage Figure 6. Driver Output Current vs. Differential Output Voltage Rev. B | Page 9 of 28 14129-009 0.02 -0.34 14129-006 DRIVER OUTPUT CURRENT (A) -0.06 -25 -24 -23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 0 -40 VDD1 = 1.7V, VDD2 = 3.0V PIN A VDD1 = 1.7V, VDD2 = 3.0V PIN B VDD1 = 5.5V, VDD2 = 5.5V PIN A VDD1 = 5.5V, VDD2 = 5.5V PIN B -0.04 14129-008 10 14129-005 SUPPLY CURRENT (mA) IDD2, 54 LOAD Data Sheet 45 36 VDD1 = VDD2 = 5V VDD1 = VDD2 = 5.5V 35 RECEIVER OUTPUT CURRENT (mA) 40 34 33 tDPLH tDPHL 32 31 30 29 28 35 30 25 20 15 10 5 27 0 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 14129-013 26 -40 14129-010 DRIVER DIFFERENTIAL PROPAGATION DELAY (ns) ADM2795E 5.0 RECEIVER OUTPUT LOW VOLTAGE (V) Figure 13. Receiver Output Current vs. Receiver Output Low Voltage Figure 10. Driver Differential Propagation Delay vs. Temperature 6 C1 VOD M1 M1 2.00V A CH1 2.12V 100ns 3 2 VDD1 = 1.8V, VDD2 = 3.3V 1 Figure 11. Driver Propagation Delay (Oscilloscope) 5 65 35 TEMPERATURE (C) -25 95 125 Figure 14. Receiver Output High Voltage vs. Temperature 60 RECEIVER OUTPUT LOW VOLTAGE (V) VDD1 = VDD2 = 5V -60 -50 -40 -30 -20 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 RECEIVER OUTPUT HIGH VOLTAGE (V) 4.5 5.0 14129-012 -10 Figure 12. Receiver Output Current vs. Receiver Output High Voltage Rev. B | Page 10 of 28 IRxD = -1mA 50 40 VDD1 = 1.8V, VDD2 = 3.3V 30 VDD1 = 5.0V, VDD2 = 5.0V 20 10 0 -55 -25 5 65 35 TEMPERATURE (C) 95 125 Figure 15. Receiver Output Low Voltage vs. Temperature 14129-015 -70 RECEIVER OUTPUT CURRENT (mA) IRxD = -1mA 4 0 -55 14129-011 C1 2.0V/DIV 1M BW: 500M VDD1 = 5.0V, VDD2 = 5.0V 5 14129-014 RECEIVER OUTPUT HIGH VOLTAGE (V) TxD Data Sheet ADM2795E 140 tPLH B 2 VOD M1 RxD 3 2.0V/DIV 2.0V/DIV 2.0V/DIV 1.4V 1M BW: 500M 1M BW: 500M 1M BW: 500M 100ns A CH3 2.56V 100ns/DIV 1.0ns/pt tPHL 100 80 60 40 20 0 -55 -25 14129-016 C1 C2 C3 M1 120 95 125 Figure 19. Receiver Propagation Delay vs. Temperature Figure 16. Receiver Propagation Delay (Oscilloscope) 250 INPUT CAPACITANCE (A, B) (pF) 5 65 35 TEMPERATURE (C) 14129-019 RECEIVER PROPAGATION DELAY (ns) A A 2 B PIN B 200 PIN A VOD 150 M1 100 RxD 50 15 35 55 75 95 115 125 130 140 JUNCTION TEMPERATURE (C) 0.14 70 0.12 SHORT-CIRCUIT CURRENT (A) 80 60 50 EN55022 40 EN55022B 30 20 100M FREQUENCY (Hz) 0.08 0.06 0.04 VDD1 = 1.7V, VDD2 = 3.0V PIN A VDD1 = 1.7V, VDD2 = 3.0V PIN B VDD1 = 5.5V, VDD2 = 5.5V PIN A VDD1 = 5.5V, VDD2 = 5.5V PIN B 0 1G 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 0 30M 2.56V 1M BW: 500M OFFSET: 25.0V A CH3 100ns/DIV 1M BW: 500M OFFSET: 25.0V 1.0ns/pt B 1M W: 500M 100ns 0.10 0.02 14129-018 10 1.0V 1.0V 2.0V/DIV 600mV Figure 20. Receiver Performance with Input Common-Mode Voltage of 25 V Figure 17. Input Capacitance (A, B) vs. Junction Temperature QUASI PEAK LEVEL (dBV/m) C1 C2 C3 M1 14129-020 -5 PIN VOLTAGE (V) Figure 18. Radiated Emissions Profile with 120 pF Capacitor to GND1 on the RxD Pin (Horizontal Scan, Data Rate = 2.5 Mbps, VDD1 = VDD2 = 5.0 V) Rev. B | Page 11 of 28 Figure 21. Short-Circuit Current over Fault Voltage Range 14129-021 0 -55 -40 -25 14129-017 3 ADM2795E Data Sheet 40 30 25 20 15 10 0 100k 1M 10M DPI FREQUENCY (Hz) 100M 1G 14129-022 5 40 POWER (dBm) 35 30 25 20 15 10 10M DPI FREQUENCY (Hz) 100M 1G Figure 23. DPI IEC 62132-4 Noise Immunity with 100 nF Decoupling on VDD1 POWER (dBm) 25 20 15 10 14129-024 5 1G 0.25 0.50 1.00 2.00 2.50 60 50 FALL TIME 40 RISE TIME 30 20 10 100 1000 Figure 26. Receiver Output (RxD) Rise/Fall Time vs. Load Capacitance 30 100M 0 LOAD CAPACITANCE (pF) 35 10M DPI FREQUENCY (Hz) 100 10 40 1M 200 0 45 0 100k 300 SIGNALING RATE (Mbps) 14129-023 5 1M 400 Figure 25. Receiver Input Differential Voltage (VID) vs. Signaling Rate 45 0 100k 500 0 RECEIVER OUTPUT (RxD) RISE/FALL TIME (ns) Figure 22. DPI IEC 62132-4 Noise Immunity with 100 nF and 10 F Decoupling on VDD1 600 14129-126 POWER (dBm) 35 700 14129-025 RECEIVER INPUT DIFFERENTIAL VOLTAGE (mV) 45 Figure 24. DPI IEC 62132-4 Noise Immunity with 100 nF and Decoupling on VDD2 Rev. B | Page 12 of 28 Data Sheet ADM2795E TEST CIRCUITS VDD2 VOUT A |VOD| VOC 14129-026 TxD R S2 CL 50pF B Figure 30. Driver Enable/Disable 375 VTST VOUT RE B CL 375 Figure 28. Driver Voltage Measurement over Common-Mode Voltage Range 14129-030 A 14129-027 60 S1 DE Figure 27. Driver Voltage Measurement |VOD3| RL 110 14129-029 R Figure 31. Receiver Propagation Delay +1.5V CL2 S1 RL -1.5V 14129-028 RLDIFF B VDD1 CL1 RE CL VOUT RE INPUT Figure 29. Driver Propagation Delay Figure 32. Receiver Enable/Disable Rev. B | Page 13 of 28 S2 14129-031 A ADM2795E Data Sheet SWITCHING CHARACTERISTICS VDD1 VDD1 TxD 0.5VDD1 0V DE 0.5VDD1 0.5VDD1 0V tPHL tPLH 0.5VDD1 tLZ tZL B 1/2 |VOD| |VOD| 0.5VDD2 A, B VOL + 0.5V A VOL tSKEW = |tPLH - tPHL| 90% POINT VOH 90% POINT A, B 10% POINT 10% POINT tR tF VOH - 0.5V 0.5VDD2 14129-032 VDIFF -VOUT tHZ 0V 14129-034 +VOUT tZH Figure 35. Driver Enable/Disable Timing Figure 33. Driver Propagation Delay, Rise/Fall Timing VDD1 RE 0.5VDD1 0.5VDD1 0V 0V 0V tPLH tPHL VOL + 0.5V OUTPUT LOW 0.5VDD1 tSKEW = |tPLH - tPHL| VOL tZH 14129-033 0.5VDD1 0.5VDD1 RxD VOH RxD tLZ tZL Figure 34. Receiver Propagation Delay RxD VOL tHZ OUTPUT HIGH 0.5VDD1 VOH VOH - 0.5V 0V Figure 36. Receiver Enable/Disable Timing Rev. B | Page 14 of 28 14129-035 A, B Data Sheet ADM2795E THEORY OF OPERATION RS-485 WITH ROBUSTNESS The ADM2795E is a 3 V to 5.5 V RS-485/RS-422 transceiver with robustness that reduces system failures when operating in harsh application environments. The ADM2795E is an RS-485/RS-422 transceiver that integrates IEC 61000-4-5 Level 4 surge protection, allowing up to 4 kV of protection on the RS-485 bus pins without the need for external protection components such as transient voltage suppressors (TVS) or TISP(R) surge protectors. The ADM2795E has IEC 61000-4-4 Level 4 EFT protection up to 2 kV and IEC 61000-4-2 Level 4 ESD protection on the bus pins. The ADM2795E is an RS-485 transceiver that offers a defined level of overvoltage fault protection in addition to IEC 61000-4-2 ESD, IEC 61000-4-4 EFT, and IEC 61000-4-5 surge protection for the RS-485 bus pins. INTEGRATED AND CERTIFIED IEC EMC SOLUTION The driver outputs/receiver inputs of RS-485 devices often experience high voltage faults resulting from short circuits to power supplies that exceed the -7 V to +12 V range specified in the TIA/EIA-485-A standard. Typically, RS-485 applications require costly external protection devices, such as positive temperature coefficient (PTC) fuses, for operation in these harsh electrical environments. In harsh electrical environments, system designers also must consider common EMC problems, choosing components to provide IEC 61000-4-2 ESD, IEC 61000-4-4 EFT, and IEC 61000-4-5 surge protection for the RS-485 bus pins. In choosing suitable EMC protection components, the system designer is faced with two challenges: complying with EMC regulations, and matching the dynamic breakdown characteristics of the EMC protection to the RS-485 transceiver. To overcome these challenges, the designer may need to run multiple design, test, and printed circuit board (PCB) board iterations, leading to a slower time to market and project budget overruns. To reduce system cost and design complexity, the ADM2795E provides certified integrated EMC protection and overvoltage fault protection on the RS-485 bus pins. The ADM2795E integrated EMC and overvoltage fault protection circuits are optimally performance matched, saving the circuit designer significant design and testing time. Figure 37 shows an isolated EMC protected RS-485 circuit layout example, which targets IEC 61000-4-2 ESD Level 4, IEC 61000-4-4 EFT Level 4, and IEC 61000-4-5 surge protection to Level 4 for the RS-485 bus pins. This circuit uses several discrete components, including two TISP surge protectors, two transient blocking units (TBUs), and one dual TVS. Due to the integrated protection components of the ADM2795E, the PCB area is significantly reduced when compared to a solution with discrete EMC protection components. DIGITAL ISOLATOR 100nF 100nF RS-485 TRANSCEIVER TISP 100nF TVS TBU TBU TISP 100nF 100nF 100nF 14129-036 ADM2795E Figure 37. ADM2795E Certified Integrated IEC 61000-4-5 Surge Solution, Saving the Designer Significant PCB Area Rev. B | Page 15 of 28 ADM2795E Data Sheet OVERVOLTAGE FAULT PROTECTION Table 11. Miswire Protection Table Abbreviations The ADM2795E is an RS-485 transceiver that offers fault protection over a 3 V to 5.5 V VDD2 operating range without the need for close examination of the logic pin state (TxD input and the DE and RE enable pins) of the RS-485 transceiver. The transceiver is also fault protected over the entire extended common-mode operating range of 25 V. Letter H L X The ADM2795E RS-485 driver outputs/receiver inputs are protected from short circuits to any voltage within the range of -42 V to +42 V ac/dc peak. The maximum short-circuit output current in a fault condition is 250 mA. The RS-485 driver includes a foldback current limiting circuit that reduces the driver current at voltages above the 25 V common-mode range limit of the transceiver (see Figure 21 in the Typical Performance Characteristics section). This current reduction due to the foldback feature allows better management of power dissipation and heating effects. VDD1 X X X X Table 12. High Voltage Miswire Protection Supply 1 2 RxD DE H/L H/L H/L H/L TxD H/L H/L H/L H/L Miswire Protection at RS-485 Outputs Pins1, 2 -42 V dc VA +42 V dc -42 V dc VB +42 V dc -42 V ac VA +42 V ac -42 V ac VB +42 V ac This is the ac/dc peak miswire voltage between Pin A and GND2, or Pin B and GND2, or between Pin A and Pin B. VA refers to the voltage on Pin A, and VB refers to the voltage on Pin B. For a high voltage miswire on the RS-485 A and B bus pins with biasing and termination resistors installed, there is a current path through the biasing network to the ADM2795E power supply pin, VDD2. To protect the ADM2795E in this scenario, the device has an integrated VDD2 protection circuit. The ADM2795E is protected against high voltage miswire events when it operates on a bus that does not have RS-485 termination or bus biasing resistors installed. A typical miswire event is where a high voltage 24 V ac/dc power supply is connected directly to RS-485 bus pin connectors. The ADM2795E can withstand miswiring faults of up to 42 V peak on the RS-485 bus pins with respect to GND2 without damage. Miswiring protection is guaranteed on the ADM2795E RS-485 A and B bus pins, and is guaranteed in the case of a hot swap of connectors to the bus pins. Table 11 and Table 12 provide a summary of the high voltage miswire protection offered by the ADM2795E. The ADM2795E is tested with 42 V dc and with 24 V 20% rms, 50 Hz/60 Hz, with both a hot plug and dc ramp test waveforms. The test is performed in both powered and unpowered/floating power supply cases, and at a range of different states for the RS-485 TxD input and the DE and RE enable pins. The RS-485 bus pins survive a high voltage miswire from Pin A to GND2, from Pin B to GND2, and between Pin A and Pin B. DIGITAL ISOLATOR VDD2 X X X X Inputs RE H/L H/L H/L H/L RS-485 NETWORK BIASING AND TERMINATION 42 V MISWIRE PROTECTION VDD1 Description High level for logic pin Low level for logic pin On or off power supply state The ADM2795E is a fault protected RS-485 device that also features protection for its power supply pin. This means that the current path through the R1 pull-up resistor does not cause damage to the VDD2 pin, although the pull-up resistor itself can be damaged if not appropriately power rated (see Figure 38). The R1 pull-up resistor power rating depends on the miswire voltage and the resistance value. If there is a miswire between the A and B pins in the Figure 38 bus setup, the ADM2795E is protected, but the RT bus termination resistor can be damaged if not appropriately power rated. The RT termination resistor power rating depends on the miswire voltage and the resistance value. VDD2 RS-485 TRANSCEIVER ADM2795E VDD2 R R1 390 RE EMC TRANSIENT PROTECTION CIRCUIT DE A B RT 220 A B R2 390 GND1 ISOLATION BARRIER GND2 14129-037 D TxD Figure 38. High Voltage Miswiring Protection for the ADM2795E with Bus Termination and Biasing Resistor Rev. B | Page 16 of 28 Data Sheet ADM2795E IEC ESD, EFT, AND SURGE PROTECTION including humidity, temperature, barometric pressure, distance, and rate of approach to the unit under test. This method is a better representation of an actual ESD event but is not as repeatable. Therefore, contact discharge is the preferred test method. Electrical and electronic equipment must be designed to meet system level IEC standards. The following are example system level IEC standards: Process control and automation: IEC 61131-2 Motor control: IEC 61800-3 Building automation: IEC 60730-1 During testing, the data port is subjected to at least 10 positive and 10 negative single discharges with a minimum 1 sec interval between each pulse. Selection of the test voltage is dependent on the system end environment. For data communication lines, these system level standards specify varying levels of protection against the following three types of high voltage transients: * * * Figure 39 shows the 8 kV contact discharge current waveform as described in the IEC 61000-4-2 specification. Some of the key waveform parameters are rise times of less than 1 ns and pulse widths of approximately 60 ns. IEC 61000-4-2 ESD IEC 61000-4-4 EFT IEC 61000-4-5 surge IPEAK 30A 90% Each of these specifications defines a test method to assess the immunity of electronic and electrical equipment against the defined phenomenon. The following sections summarize each of these tests. The ADM2795E is fully tested in accordance with these IEC EMC specifications, and is certified IEC EMC compliant. I30ns 16A Electrostatic Discharge (ESD) I60ns ESD is the sudden transfer of electrostatic charge between bodies at different potentials caused by near contact or induced by an electric field. ESD has the characteristics of high current in a short time period. The primary purpose of the IEC 61000-4-2 test is to determine the immunity of systems to external ESD events outside the system during operation. IEC 61000-4-2 describes testing using the following two coupling methods: contact discharge and air gap discharge. Contact discharge implies a direct contact between the discharge gun and the unit under test. During air discharge testing, the charged electrode of the discharge gun is moved toward the unit under test until a discharge occurs as an arc across the air gap. The discharge gun does not make direct contact with the unit under test. A number of factors affect the results and repeatability of the air discharge test, VDD1 DIGITAL ISOLATOR RxD 8A 10% 60ns 30ns Figure 39. IEC 61000-4-2 ESD Waveform (8 kV) Figure 40 shows an example test setup where the ADM2795E evaluation board is tested to both contact discharge and air discharge for the IEC 61000-4-2 ESD standard. Testing was performed with the IEC ESD gun connected to the local bus, GND2. In testing to GND2, the ADM2795E is robust to IEC 61000-4-2 events and passes the highest level recognized in the standard, Level 4, which defines a contact discharge voltage of 8 kV and an air discharge voltage of 15 kV. VDD2 RS-485 TRANSCEIVER ADM2795E R RE EMC TRANSIENT PROTECTION CIRCUIT DE A IEC ESD GUN B D GND1 ISOLATION BARRIER GND2 14129-040 TxD TIME tR = 0.7ns TO 1ns 14129-038 * * * Figure 40. IEC 61000-4-2 ESD Testing to GND1 or GND2 Rev. B | Page 17 of 28 ADM2795E Data Sheet Testing was also performed with the IEC ESD gun connected to the logic side GND1. Testing to GND1 demonstrates the robustness of the ADM2795E isolation barrier. The isolation barrier is capable of withstanding IEC 61000-4-2 ESD to 9 kV contact and to 8 kV air. Testing was performed in normal transceiver operation, with the ADM2795E clocking data at 2.5 Mbps. Table 13 and Table 16 summarize the certified test results. Table 13. IEC 61000-4-2 Certified Test Results ESD Gun Connected to GND2 IEC 61000-4-2 Test Result 15 kV (air), 8 kV (contact), Level 4 protection Withstands 8 kV (air), 9 kV (contact) GND1 Certified Result Yes in IEC 61000-4-4 attempts to simulate the interference resulting from these types of events. Figure 42 shows the EFT 50 load waveforms. The EFT waveform is described in terms of a voltage across a 50 impedance from a generator with a 50 output impedance. The output waveform consists of a 15 ms burst of 5 kHz high voltage transients repeated at 300 ms intervals. The EFT test is also performed with a 750 s burst at a higher 100 kHz frequency. Each individual pulse has a rise time of 5 ns and a pulse duration of 50 ns, measured between the 50% point on the rising and falling edges of the waveform. The total energy in a single EFT pulse is similar to that in an ESD pulse. Yes VPEAK 100% Figure 41 shows the 8 kV contact discharge current waveform from the IEC 61000-4-2 standard compared to the HBM ESD 8 kV waveform. Figure 41 shows that the two standards each specify a very different waveform shape and peak current. The peak current associated with a IEC 61000-4-2 8 kV pulse is 30 A, while the corresponding peak current for HBM ESD is more than five times less, at 5.33 A. The other difference is the rise time of the initial voltage spike, with IEC 61000-4-2 ESD having a much faster rise time of 1 ns, compared to the 10 ns associated with the HBM ESD waveform. The amount of power associated with an IEC ESD waveform is much greater than that of an HBM ESD waveform. The ADM2795E with IEC 61000-4-2 ESD ratings is better suited for operation in harsh environments compared to other RS-485 transceivers that state varying levels of HBM ESD protection. 90% tR = 5ns 30% tD = 5ns 30% SINGLE PULSE 50% tD tR 10% TIME (ns) 15ms BURST OF PULSES TIME (ms) IPEAK VPEAK 30A 90% 300ms REPETITIVE BURSTS I30ns 16A TIME (ms) Figure 42. IEC 61000-4-4 EFT 50 Load Waveforms 8A 5.33A HBM ESD 8kV 10% 10ns 30ns 60ns TIME tR = 0.7ns TO 1ns 14129-039 I60ns 14129-041 IEC 61000-4-2 ESD 8kV Figure 41. IEC 61000-4-2 ESD Waveform (8 kV) Compared to HBM ESD Waveform (8 kV) Electrical Fast Transients (EFTs) EFT testing involves coupling a number of extremely fast transient impulses onto the signal lines to represent transient disturbances (associated with external switching circuits that are capacitively coupled onto the communication ports), which may include relay and switch contact bounce or transients originating from the switching of inductive or capacitive loads--all of which are very common in industrial environments. The EFT test defined During testing, these EFT fast burst transients are coupled onto the communication lines using a capacitive clamp, as shown in Figure 43. The EFT is capacitively coupled onto the communication lines by the clamp rather than direct contact. This clamp also reduces the loading caused by the low output impedance of the EFT generator. The coupling capacitance between the clamp and cable depends on cable diameter, shielding, and insulation on the cable. The EFT clamp edge is placed 50 cm from the equipment under test (EUT) (ADM2795E evaluation board). The EFT generator is set up for either 5 kHz or 100 kHz repetitive EFT bursts. The ADM2795E was tested in both 5 kHz and 100 kHz test setups. With the EFT clamp connected to GND2, the ADM2795E is robust to IEC 61000-4-4 EFT transients and protects against the highest level recognized in the standard, Level 4, which defines Rev. B | Page 18 of 28 Data Sheet ADM2795E defines waveforms, test methods, and test levels for evaluating immunity against these destructive surges. a voltage level of 2 kV. With the IEC 61000-4-4 EFT clamp connected to GND1, the ADM2795E is robust to IEC 61000-4-4 EFT transients and withstands up to 2 kV. Testing was performed in normal transceiver operation, with the ADM2795E clocking data at 2.5 Mbps. The results shown in Table 14 are valid for a setup with or without an RS-485 cable shield connection to GND2. The ADM2795E withstands up to 2 kV IEC 61000-4-4 EFT without damage. Table 14 and Table 16 summarize the certified test results. The waveforms are specified as the outputs of a waveform generator in terms of open circuit voltage and short-circuit current. Two waveforms are described. The 10 s/700 s combination waveform is used to test ports intended for connection to symmetrical communication lines: for example, telephone exchange lines. The 1.2 s/50 s combination waveform generator is used in all other cases, in particular short distance signal connections. For RS-485 ports, the 1.2 s/50 s waveform is predominantly used and is described in this section. The waveform generator has an effective output impedance of 2 ; therefore, the surge transient has high currents associated with it. Table 14. IEC 61000-4-4 Certified Test Results Certified Result Yes Yes IEC 61000-4-4 Test Result 2 kV Level 4 protection Withstands 2 kV Figure 44 shows the 1.2 s and 50 s surge transient waveform. ESD and EFT have similar rise times, pulse widths, and energy levels; however, the surge pulse has a rise time of 1.25 s and the pulse width is 50 s. Additionally, the surge pulse energy is three to four orders of magnitude larger than the energy in an ESD or EFT pulse. Therefore, the surge transient is considered the most severe of the EMC transients. Surge Surge transients are caused by overvoltage from switching or lightning transients. Switching transients can result from power system switching, load changes in power distribution systems, or various system faults such as short circuits. Lightning transients can be a result of high currents and voltages injected into the circuit from nearby lightning strikes. IEC 61000-4-5 VDD2 VDD1 RS-485 TRANSCEIVER DIGITAL ISOLATOR RxD IEC EFT GENERATOR 5kHz, 100kHz ADM2795E R RE EMC TRANSIENT PROTECTION CIRCUIT DE A RS-485 CABLE B IEC EFT CLAMP D TxD GND1 GND2 RS-485 CABLE SHIELD 14129-042 ISOLATION BARRIER Figure 43. IEC 61000-4-4 EFT Testing to GND1 or GND2 VPEAK 100% 90% 50% t2 t1 = 1.2s 30% t2 = 50s 20% 10% t1 30% MAX Figure 44. IEC 61000-4-5 Surge 1.2 s/50 s Waveform Rev. B | Page 19 of 28 TIME (s) 14129-043 EFT Clamp Connected to GND2 GND1 ADM2795E Data Sheet VDD2 VDD1 DIGITAL ISOLATOR RxD RS-485 TRANSCEIVER ADM2795E R COUPLING NETWORK RE EMC TRANSIENT PROTECTION CIRCUIT DE 80 A B IEC SURGE GENERATOR CD 80 D GND1 ISOLATION BARRIER GND2 14129-044 TxD Figure 45. IEC 61000-4-5 Surge Testing to GND1 or GND2 IEC 61000-4-5 surge testing involves using a coupling/decoupling network (CDN) to couple the surge transient into the RS-485 A and B bus pins. The coupling network for a half-duplex RS-485 device consists of an 80 resistor on both the A and B lines and a coupling device. The total parallel sum of the resistance is 40 . The coupling device can be capacitors, gas arrestors, clamping devices, or any method that allows the EUT to function correctly during the applied test. During the surge test, five positive and five negative pulses are applied to the data ports with a maximum time interval of one minute between each pulse. The standard states that the device must be set up in normal operating conditions for the duration of the test. Figure 45 shows the test setup for surge testing. Testing is performed in normal transceiver operation, with the ADM2795E clocking data at 2.5 Mbps. With the IEC surge generator connected to GND2, the ADM2795E is robust to IEC 61000-4-5 events and protects against the highest level recognized in the standard, Level 4, which defines a peak voltage of 4 kV. With the IEC surge generator connected to GND1, the ADM2795E is robust to IEC 61000-4-5 events and withstands up to 4 kV surge. The ADM2795E withstands up to 4 kV IEC 61000-4-5 surge without damage and with no bit errors in data communications. Testing to GND1 demonstrates the robustness of the ADM2795E isolation barrier. Table 15 and Table 16 summarize the certified test results. Table 15. IEC 61000-4-5 Certified Test Results Surge Generator Connected to GND2 GND1 IEC 61000-4-5 Test Result 4 kV Level 4 protection Withstands 4 kV Certified Result Yes Yes Table 16 summarizes the ADM2795E performance and classification achieved for the noted IEC system level EMC standards. The performance corresponds to each classification as follows: * * * * Class A--normal operation Class B--temporary loss of performance (bit errors) Class C--system needs reset Class D--permanent loss of function Table 16. Summary of Certified EMC System Level Classifications for the ADM2795E Test IEC 61000-4-5 Surge IEC 61000-4-4 Electrical Fast Transient (EFT) IEC 61000-4-2 Electrostatic Discharge (ESD) IEC 61000-4-6 Conducted RF Immunity IEC 61000-4-3 Radiated RF Immunity IEC 61000-4-8 Magnetic Immunity Ground Connection GND1 GND2 GND1 GND2 GND1 GND2 GND1 GND2 GND2 GND2 Rev. B | Page 20 of 28 Classification Class A Class B Class B Class B Class B Class B Class A Class A Class A Class A Highest Pass Level 4 kV 4 kV 2 kV 2 kV 8 kV (air), 9 kV (contact) 15 kV (air), 8 kV (contact) 10 V/m rms 10 V/m rms 30 V/m 100 A/m Data Sheet ADM2795E IEC CONDUCTED, RADIATED, AND MAGNETIC IMMUNITY Table 17. IEC 61000-4-6 EUT and Equipment Parameter IEC 61000-4-6 Clamp IEC 61000-4-6 Test Level IEC 61000-4-6 Conducted RF Immunity The IEC 61000-4-6 conducted immunity test is applicable to products that operate in environments where RF fields are present and that are connected to mains supplies or other networks (signal or control lines). The source of conducted disturbances are electromagnetic fields, emanating from RF transmitters that may act on the whole length of cables connected to installed equipment. EUT EUT Data Rate EUT Power Cable Between EUT In the IEC 61000-4-6 test, an RF voltage is swept/stepped from 150 kHz to 80 MHz or 100 MHz. The RF voltage is amplitude modulated 80% at 1 kHz. One ADM2795E evaluation board is tested to Level 3, which is the highest test level of 10 V. For IEC 61000-4-6 testing, the stress signal is applied by using the clamp detailed in Table 17. The clamp is placed on the communications cable between two ADM2795E transceivers. For all testing, the equipment and EUT setup are as described in Table 17 and Figure 46. Cable Termination Pass/Fail Criteria Details Schaffner KEMZ 801, placed at 30 cm from the EUT Level 3, 0.15 MHz to 80 MHz, 10 V/m rms, 80% amplitude modulated (AM) by a 1 kHz sinusoidal EVAL-ADM2795EEBZ 2.5 Mbps 9 V battery at VDD1 and VDD2, regulated on EUT to 5 V 5 m, Unitronic(R) Profibus, 22 American wire gauge (AWG ) 120 resistor at both cable ends Pass: data at receiver with a pulse width distortion within 10% of mean Table 18. IEC 61000-4-6 Certified Test Results Clamp Location from EUT (cm) 30 30 30 30 Table 17 shows the test results where the EUT pass IEC 61000-4-6 to Level 3. For all of the tests, the IEC 61000-4-6 clamp is placed at the EVAL-ADM2795EEBZ EUT, and the cable shield is either floating or Earth grounded. The second EVAL-ADM2795EEBZ (auxiliary equipment) was placed on the network to terminate the communications bus. The IEC 61000-4-6 generator clamp was either connected to GND1 or GND2 of the ADM2795E EUT to provide a return current path for the IEC 61000-4-6 transient current. Cable Shield Floating Earthed Floating Earthed Current Return Path GND1 GND1 GND2 GND2 IEC 61000-4-6 Test Frequency (MHz) 0.15 to 80 0.15 to 80 0.15 to 80 0.15 to 80 Certified Result Pass Pass Pass Pass The ADM2795E evaluation board is tested and certified to pass IEC 61000-4-6 conducted RF immunity testing to Level 3 at 10 V/m rms, in a variety of configurations as described in Table 16 and Table 17. VDD1 DIGITAL ISOLATOR VDD2 VDD2 RS-485 TRANSCEIVER ADM2795E EUT RxD R RE EMC TRANSIENT PROTECTION CIRCUIT DE A A B IEC 61000-4-6 CLAMP ISOLATION BARRIER GND2 RS-485 CABLE SHIELD B DIGITAL ISOLATOR RxD R RE EMC TRANSIENT PROTECTION CIRCUIT DE D GND2 TxD GND1 14129-046 GND1 RS-485 TRANSCEIVER AUXILIARY EQUIPMENT RT D TxD ADM2795E IEC 61000-4-6 GENERATOR VDD1 Figure 46. IEC 61000-4-6 Conducted RF Immunity Example Test Setup Testing to GND1 or GND2 Rev. B | Page 21 of 28 ADM2795E Data Sheet IEC 61000-4-3 Radiated RF Immunity IEC 61000-4-8 Magnetic Immunity Testing to IEC 61000-4-3 ensures that electronic equipment is immune to commonly occurring radiated RF fields. Some commonly occurring unintentional RF emitting devices in an industrial application are electric motors and welders. Testing to IEC 61000-4-8 ensures that electronic equipment is immune to commonly occurring magnetic fields. The source of magnetic fields in typical industrial communication applications is power line current or 50 Hz/60 Hz transformers in close proximity to the equipment. In the IEC 61000-4-3 test, a radiated RF field is generated by an antenna in a shielded anechoic chamber using a precalibrated field, swept from 80 MHz to 2.7 GHz. The RF voltage is amplitude modulated 80% at 1 kHz. Each face of the EUT is subjected to vertical and horizontal polarizations. In the IEC 61000-4-8 test, a controlled magnetic field of defined field strength is produced by driving a large coil (induction coil) with a test current generator. The EUT is placed at the center of the induction coil, subjecting the EUT to a magnetic field. Figure 47 shows the test setup with the EVAL-ADM2795EEBZ, the EUT, placed in an anechoic chamber, powered with two 9 V batteries. The EVAL-ADM2795EEBZ on board regulators power VDD1 at 5.0 V and VDD2 at 5.0 V. The EVAL-ADM2795EEBZ is loaded with a 120 termination resistor for the duration of the test. A pattern generator provides a 2.5 Mbps data input to the ADM2795E TxD pin. The ADM2795E receiver output (RxD) is monitored with an oscilloscope. Figure 48 shows the test setup with the EVAL-ADM2795EEBZ, the EUT, placed in an anechoic chamber, powered with two 9 V batteries. The EVAL-ADM2795EEBZ on board regulators power VDD1 at 5.0 V and VDD2 at 5.0 V. The EVAL-ADM2795EEBZ is loaded with a 120 termination resistor for the duration of the test. A pattern generator provides a 2.5 Mbps data input to the ADM2795E TxD pin. The ADM2795E receiver output (RxD) is monitored with an oscilloscope. The pass criteria chosen is less than a 10% change in the bit width of the RxD signal in the presence of the IEC 61000-4-3 radiated RF field. The pass criteria chosen is less than a 10% change in the bit width of the RxD signal in the presence of the IEC 61000-4-8 magnetic field. The ADM2795E evaluation board is tested and certified to pass IEC 61000-4-3 radiated RF immunity testing to Level 4 (30 V/m). Level 4 is the highest level specified in the IEC 61000-4-3 standard. The ADM2795E evaluation board is tested and certified to pass IEC 61000-4-8 magnetic immunity testing to Level 5 (100 A/m). Level 5 is the highest level specified in the IEC 61000-4-8 standard. EUT TESTED ON ALL FOUR SIDES ANECHOIC CHAMBER RF ABSORBING MATERIAL EUT INDUCTION LOOP EVAL-ADM2795EEBZ VDD1 9V BATTERY VDD2 9V BATTERY VDD1 9V BATTERY TRANSMIT ANTENNA VDD2 9V BATTERY EVAL-ADM2795EEBZ IEC 61000-4-8 TEST CURRENT GENERATOR EUT EUT ISOLATION BARRIER ANTENNA AT 1 METER TO 3 METERS FROM EUT ISOLATION BARRIER POWER MONITOR AND AMPLIFIER 14129-148 PATTERN GENERATOR TxD DRIVER INPUT PATTERN GENERATOR TxD DRIVER INPUT Figure 48. Testing for IEC 61000-4-8 Magnetic Immunity Figure 47. Testing for IEC 61000-4-3 Radiated RF Immunity Rev. B | Page 22 of 28 14129-149 OSCILLOSCOPE MONITORING RxD RECEIVER OUTPUT OSCILLOSCOPE MONITORING RxD RECEIVER OUTPUT Data Sheet ADM2795E APPLICATIONS INFORMATION RADIATED EMISSIONS AND PCB LAYOUT The ADM2795E meets stringent electromagnetic interference (EMI) emissions targets (EN55022 Class B) with minimal PCB layout considerations. To achieve a 6 dBV/m margin from EN55022 Class B limits, add a 120 pF, 0603 body size capacitor on the PCB trace connected to the RxD pin and GND1 (see Figure 49). Place the capacitor at 5 mm from the RxD pin for optimal performance. The ADM2795E evaluation board user guide provides an example PCB layout. Figure 18 shows a typical performance plot of the ADM2795E EN55022 radiated emissions profile (with a 120 pF capacitor to GND1 on the RxD pin).The effect of adding load capacitance on the RxD pin is shown in the typical waveform rise and fall times in Figure 26. NOISE IMMUNITY Direct power injection (DPI) measures the ability of a component to reject noise injected onto the power supply or input pins. The ADM2795E was tested to the DPI IEC 62132-4 standard, with a high power noise source capacitively coupled into either the VDD1 or VDD2 power supply pin. The noise source was swept through a 300 kHz to 1 GHz frequency band. During DPI IEC 62132-4 testing, the ADM2795E TxD pin was clocked at 2.5 Mbps, and the clock data output on the RxD pin was monitored for errors (loopback test mode). The fail criteria was defined as greater than 10% change in the bit width of the RxD signal. Figure 50 shows a test setup, with the DPI noise source injected through a 6.8 nF capacitor on the ADM2795E VDD1 power supply pin. Figure 22 to Figure 24 in the Typical Performance Characteristics section show the fail point for the ADM2795E across the noise power (dBm) vs. DPI frequency (Hz). Figure 21 shows that the addition of a 10 F decoupling capacitor, in addition to the standard 100 nF decoupling capacitor, improves low frequency noise immunity. VDD1 Performance to the IEC 62132-4 standard was evaluated for the ADM2795E and compared to other isolators/transceivers available in the market. The ADM2795E noise immunity performance exceeds that of other similar products. The ADM2795E maintains excellent performance over frequency, but other isolation products exhibit bit errors in the 200 MHz to 700 MHz frequency band. FULLY RS-485 COMPLIANT OVER AN EXTENDED 25 V COMMON-MODE VOLTAGE RANGE The ADM2795E is an RS-485 transceiver that offers an extended common-mode input range of 25 V across an operating voltage range of 3 V to 5.5 V, while still meeting or exceeding compliance with TIA/EIA RS-485/RS-422 standards. The TIA/EIA RS-485/ RS-422 standards specify a bus differential voltage of at least 1.5 V across the common-mode voltage range. In addition, when powered at greater than 4.5 V VDD2, the ADM2795E driver output is a minimum 2.1 V |VOD|, meeting the requirements for a Profibus compliant RS-485 driver. The extended common-mode input voltage range of 25 V improves system robustness over long cable lengths, where large differences in ground potential between RS-485 transceivers are possible. The extended common-mode input voltage range of 25 V improves data communication reliability in noisy environments over long cable lengths where ground loop voltages are possible. 1.7 V TO 5.5 V VDD1 LOGIC SUPPLY The ADM2795E features a logic supply pin, VDD1, for flexible digital interface operational to voltages as low as 1.7 V. The VDD1 pin powers the logic inputs (TxD input, and DE and RE control pins) and the RxD output. These pins interface with logic devices such as universal asynchronous receiver/transmitters (UARTs), application specific integrated circuits (ASICs), and microcontrollers. Many of these devices use power supplies significantly lower than 5 V. 100nF 100nF GND1 TxD DE RE B ADM2795E V 100nF DD2 GND2 A NIC GND2 GND1 GND2 Figure 49. Recommended PCB Layout to Meet EN55022 Class B Radiated Emissions Rev. B | Page 23 of 28 14129-045 RxD 120pF VDD2 GND2 ADM2795E Data Sheet DPI NOISE SOURCE INJECTION TWO FERRITES BLMBD102SN1 VDD1 5V 220H 6.8nF VDD1 C1 10F C2 100nF VDD2 100nF GND1 MINIMUM 400 IMPEDANCE ACROSS 300kHz TO 1GHz RANGE VDD2 5V ADM2795E 2.5Mbps CLOCK TxD A RS-485A RxD B 60 14129-047 RS-485B NOTES 1. SIMPLIFIED DIAGRAM, ALL PINS NOT SHOWN. Figure 50. Typical Setup for DPI IEC 62132-4 Noise Immunity Test TRUTH TABLES RECEIVER FAIL-SAFE Table 20 and Table 21 use the abbreviations shown in Table 19. VDD1 supplies the DE, TxD, RE, and RxD pins only. The receiver input includes a fail-safe feature that guarantees a logic high RxD output when the A and B inputs are floating, open circuit, or short circuit. A logic high RxD output is guaranteed in a terminated transmission line with all drivers disabled. This fail-safe RxD guaranteed output logic high is implemented by setting the receiver input threshold between -30 mV and -200 mV. If the differential receiver input voltage (A - B) is greater than or equal to -30 mV, RxD is logic high. If A - B is less than or equal to -200 mV, RxD is logic low. In the case of a terminated bus with all transmitters disabled, the receiver differential input voltage is pulled to 0 V by the termination. With the receiver thresholds of the ADM2795E, this results in a RxD output logic high with a 30 mV minimum noise margin. Table 19. Truth Table Abbreviations Letter H I L X Z NC Description High level Indeterminate Low level Any state High impedance (off ) Disconnected Table 20. Transmitting Truth Table VDD2 On On On On On On Off Off Supply Status VDD1 On On On Off Off Off On Off DE H H L H H L X X Inputs TxD H L X H L X X X A H L Z I I I Z Z Outputs B L H Z I I I Z Z Table 21. Receiving Truth Table Supply Status VDD2 On On On On On On On On On On Off Off VDD1 On On Off Off On Off On Off On Off Off Off Inputs A-B >-0.03 V <-0.2 V >-0.03 V <-0.2 V -0.2 V < A - B < -0.03 V -0.2 V < A - B < -0.03 V Inputs open/shorted Inputs open/shorted X X X X Outputs RE L L L L L L L L H H H L or NC RxD H L I I I I H I Z I I I RS-485 DATA RATE AND BUS CAPACITANCE The data rate and bus node capability of the ADM2795E are dependent on the operating temperature of the device. As the operating temperature of the ADM2795E is increased, the capacitance of the ADM2795E integrated EMC protection circuitry is also increased. The driver output structures of the ADM2795E can be simplified as low-pass filter structures, with a given resistance and capacitance. As the operating temperature increases, the capacitance increases. The low-pass filter effectively works to decrease the maximum data rate that can be driven on the RS-485 bus pins. INSULATION WEAR OUT The lifetime of insulation caused by wear out is determined by its thickness, material properties, and the voltage stress applied. It is important to verify that the product lifetime is adequate at the application working voltage. The working voltage supported by an isolator for wear out may not be the same as the working voltage supported for tracking. The working voltage applicable to tracking is specified in most standards. Testing and modeling show that the primary driver of longterm degradation is displacement current in the polyimide insulation causing incremental damage. The stress on the insulation can be broken down into broad categories, such as dc stress, which causes very little wear out because there is no Rev. B | Page 24 of 28 Data Sheet ADM2795E displacement current, and an ac component time varying voltage stress, which causes wear out. The ratings in certification documents are typically based on 60 Hz sinusoidal stress because this reflects isolation from the line voltage. However, many practical applications have combinations of 60 Hz ac and dc across the barrier as shown in Equation 1. Because only the ac portion of the stress causes wear out, the equation can be rearranged to solve for the ac rms voltage, as shown in Equation 2. For insulation wear out with the polyimide materials used in the ADM2795E, the ac rms voltage determines the product lifetime. V RMS V AC V DC 2 (1) V AC RMS V RMS 2 VDC 2 (2) RMS 2 or where: VRMS is the total rms working voltage. VAC RMS is the time varying portion of the working voltage. VDC is the dc offset of the working voltage. TIME The working voltage across the barrier from Equation 1 is 2 VDC 2 14129-048 ISOLATION VOLTAGE VDC Figure 51. Critical Voltage Example RMS V AC RMS 466 2 400 2 VAC RMS = 240 V rms In this case, the ac rms voltage is simply the line voltage of 240 V rms. This calculation is more relevant when the waveform is not sinusoidal. The value is compared to the limits for working voltage in Table 8 for the expected lifetime, less than a 60 Hz sine wave, and it is well within the limit for a 50-year service life. When a PCB is inserted into a hot (or powered) backplane, differential disturbances to the data bus can lead to data errors. The ADM2795E was lab tested to ensure that the RS-485 A and B bus pins did not output spurious data during a power-up/powerdown event, which simulated a PCB hot insertion. The power supply ramp test rates were 0 V to 5 V in 300 s (fast ramp rate), and 0 V to 5 V in 9.5 ms (slow ramp rate). For these ramp rates, the RS-485 A and B outputs were monitored and with no output glitches were observed. ROBUST HALF-DUPLEX RS-485 NETWORK VAC RMS VRMS V AC V AC RMS VRMS 2 VDC 2 HOT SWAP CAPABILITY The following example frequently arises in power conversion applications. Assume that the line voltage on one side of the isolation is 240 V ac rms and a 400 V dc bus voltage is present on the other side of the isolation barrier. The isolator material is polyimide. To establish the critical voltages in determining the creepage, clearance, and lifetime of a device, see Figure 51 and the following equations. VRMS To determine if the lifetime is adequate, obtain the time varying portion of the working voltage. To obtain the ac rms voltage, use Equation 2. Note that the dc working voltage limit in Table 8 is set by the creepage of the package as specified in IEC 60664-1. This value can differ for specific system level standards. Calculation and Use of Parameters Example VPEAK This VRMS value is the working voltage used together with the material group and pollution degree when looking up the creepage required by a system standard. Figure 52 shows a robust isolated RS-485 communications network, with bus communications running over 1000 feet of cabling. Over long cable runs with multiple RS-485 nodes, a number of hazards can either corrupt data communication or even cause permanent damage to the RS-485 interface. The ADM2795E provides robust protection against high voltage faults to bus power supplies and EMC transients, such as an IEC 61000-4-5 surge. In addition, the ADM2795E has an extended common-mode input range of 25 V, which allows 25 V of ground potential difference between the isolated GND2 pins of two or more ADM2795E devices. VRMS 2402 4002 VRMS = 466 V Rev. B | Page 25 of 28 ADM2795E DIGITAL ISOLATOR 24V POWER - SUPPLY + VDD2 RS-485 TRANSCEIVER RxD MISWIRE TO A 24V SUPPLY VDD2 EMC TRANSIENT RS-485 TRANSCEIVER ADM2795E DE A A RT B B RE EMC TRANSIENT PROTECTION CIRCUIT DE D D ISOLATION BARRIER VDD1 DIGITAL ISOLATOR RxD VDD2 RS-485 TRANSCEIVER RS-485 TRANSCEIVER ADM2795E VDD1 DIGITAL ISOLATOR ADM2795E RxD R EMC TRANSIENT PROTECTION CIRCUIT DE A A B B RE EMC TRANSIENT PROTECTION CIRCUIT DE D D ISOLATION BARRIER GND1 VDD2 R GND1 TxD GND2 GND2 RE TxD RxD R EMC TRANSIENT PROTECTION CIRCUIT GND1 DIGITAL ISOLATOR ADM2795E R RE TxD VDD1 GND2 COMMUINICATION WITH 25V POTENTIAL DIFFERENCE BETWEEN ISOLATED BUS GROUNDS GND2 Figure 52. Robust Half-Duplex Isolated RS-485 Communication Network Rev. B | Page 26 of 28 TxD GND1 14129-049 VDD1 Data Sheet Data Sheet ADM2795E The ADuM6028 can be powered from either a 3.3 V or 5 V supply, depending on the selected model. The VDD1 pin of the ADM2795E can be powered from the same rail as the isolated dc to dc converter, or the device can alternatively be connected to the low voltage supply rail of a microcontroller or logic device that operates with an input supply voltage between 1.7 V and 5.5 V. EMC COMPLIANT AND FAULT PROTECTED SIGNAL AND POWER ISOLATED RS-485 NODE The circuit shown in Figure 53 demonstrates a fully isolated RS-485 node using the ADM2795E and the ADuM6028 isolated dc to dc converter. The small form factor and low radiated emissions of the ADuM6028 make the combination of the two devices ideal for space constrained applications that require high voltage 42 V fault protection on the bus pins as well as integrated Level 4 EMC protection to IEC standards against ESD, EFT, and surge. In applications where 5 kV of isolation is not required, the ADuM5028 can be used in place of the ADuM6028. See Table 22 for device selection and the maximum allowed ambient temperature. The ADuM6028 can deliver a minimum of 60 mA of current at the 3.3 V output supply in a compact 5.85 mm x 10.31 mm low profile footprint. When the ADM2795E is fully loaded and switching at 2.5 Mbps, the device consumes up to 50 mA at 3.3 V, which can be supplied from the ADuM6028. Two surface-mount ferrite beads are used to meet EN 55022 Class B radiated emissions requirements on a standard 2-layer PCB. See the ADuM6028 data sheet for implementation details. In applications where a 5 V VDD2 supply voltage is preferred on the ADM2795E, users can replace the ADuM6028 with the ADuM6020, which can provide the necessary 100 mA for up to 105C operation in a compact 16-lead wide body SOIC package. Table 22. Isolated DC to DC Converter Selection Table Isolation Rating (kV) 5 5 2.5 2.5 VDDP Supply Voltage (V) 5 3.3 5 3.3 Maximum Operating Temperature (C) 85 105 85 105 Isolated DC to DC Converter ADuM6028-5BRIZ ADuM6028-3BRIZ ADuM5028-5BRIZ ADuM5028-3BRIZ ISOLATION BARRIER ADuM6028 +5V OR +3.3V GND1 VDDP 0.1F GND1 PCS 1 8 7 2 OSC 3 RECT REG 6 5 4 VSEL GNDISO FERRITE BEAD VISO GNDISO 10F 0.22uF FERRITE BEAD ISOLATED +3.3V SUPPLY +1.7V TO +5.5V 0.1F VDD1 0.1F DIGITAL ISOLATOR VDD2 RS-485 TRANSCEIVER RxD ADM2795E R RE EMC TRANSIENT PROTECTION CIRCUIT DE A B D TxD GND 1 ISOLATION BARRIER GND2 14129-153 PDIS Figure 53. 2.5 Mbps, 5 kV Signal and Power Isolated RS-485 Node with 42 V Fault Protection and Level 4 EMC Protection (3.3 V Transceiver) Rev. B | Page 27 of 28 ADM2795E Data Sheet OUTLINE DIMENSIONS 10.50 (0.4134) 10.10 (0.3976) 9 16 7.60 (0.2992) 7.40 (0.2913) 8 1.27 (0.0500) BSC 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 0.51 (0.0201) 0.31 (0.0122) 10.65 (0.4193) 10.00 (0.3937) 0.75 (0.0295) 45 0.25 (0.0098) 2.65 (0.1043) 2.35 (0.0925) SEATING PLANE 8 0 0.33 (0.0130) 0.20 (0.0079) 1.27 (0.0500) 0.40 (0.0157) COMPLIANT TO JEDEC STANDARDS MS-013-AA CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN. 03-27-2007-B 1 Figure 54. 16-Lead Standard Small Outline Package [SOIC_W] Wide Body (RW-16) Dimensions shown in millimeters and (inches) ORDERING GUIDE Model 1 ADM2795EBRWZ ADM2795EBRWZ-RL7 ADM2795EARWZ ADM2795EARWZ-RL7 EVAL-ADM2795EEBZ 1 Temperature Range -40C to +125C -40C to +125C -40C to +85C -40C to +85C Package Description 16-Lead Standard Small Outline Package [SOIC_W] 16-Lead Standard Small Outline Package [SOIC_W], 7" Reel 16-Lead Standard Small Outline Package [SOIC_W] 16-Lead Standard Small Outline Package [SOIC_W], 7" Reel Evaluation Board Z = RoHS Compliant Part. (c)2016-2020 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D14129-1/20(B) Rev. B | Page 28 of 28 Package Option RW-16 RW-16 RW-16 RW-16 Ordering Quantity 400 400